Electrostatic discharge protection in a monolithic gate driver having multiple voltage domains

ABSTRACT

A gate driver integrated circuit includes a high-side region that operates in a first voltage domain according to a first pair of supply terminals that include a first lower supply terminal and a first higher supply terminal; a low-side region that operates in a second voltage domain according to a second pair of supply terminals; a low-voltage region the operates in a third voltage domain; at least one termination region that electrically isolates the high-side region from the low-side region and the low-voltage region; a first electrostatic device arranged in the high-side region and connected to the first pair of supply terminals; a second electrostatic device arranged in the low-side region and connected to the second pair of supply terminals; and a third electrostatic device connected to a lower supply terminal of the first pair of supply terminals and is coupled in series with the first electrostatic device.

BACKGROUND

A high voltage (HV) gate driver circuit may include a low voltage (LV)gate driver used to drive a low-side transistor switch and an HV gatedriver used to drive a high-side transistor switch. The LV gate driveris arranged in a low voltage domain, whereas the HV gate driver isarranged in a high voltage domain. In practice, the gate driver alsoincludes a termination region that isolates the high voltage domain fromthe low voltage domain, and may be referred to as an isolationtermination region. Thus, the termination region provides a voltageisolation barrier between the two voltage domains.

Electrostatic discharge (ESD) protection is typically needed for allpads of an integrated circuit (IC). However, ESD protection consumesarea and cost due to silicon usage. A voltage rating of an ESD device isthe voltage difference between its input and out terminals. The largerthe voltage rating of an ESD device, the more die area is needed for theESD device. Thus, the higher the cost.

Therefore, providing ESD protection between multiple voltage domains ata smaller footprint and at a lower cost may be desirable.

SUMMARY

Embodiments provide a gate driver integrated circuit, including: ahigh-side region that operates in a first voltage domain according to afirst pair of supply terminals that include a first lower supplyterminal and a first higher supply terminal; a low-side region thatoperates in a second voltage domain lower than the first voltage domainaccording to a second pair of supply terminals that include a secondlower supply terminal and a second higher supply terminal; a low-voltageregion the operates in a third voltage domain lower than the secondvoltage domain; at least one termination region that electricallyisolates the high-side region from the low-side region and thelow-voltage region; a first electrostatic device arranged in thehigh-side region and connected to the first pair of supply terminals; asecond electrostatic device arranged in the low-side region andconnected to the second pair of supply terminals; and a thirdelectrostatic device connected to the first lower supply terminal of thefirst pair of supply terminals such that the third electrostatic deviceis coupled in series with the first electrostatic device.

Embodiments provide a method of operating a gate driver integratedcircuit. The method includes: operating at least one high-side device ina first voltage domain according to a first pair of supply terminalsthat include a first lower supply terminal and a first higher supplyterminal; operating at least one low-side device in a second voltagedomain lower than the first voltage domain according to a second pair ofsupply terminals that include a second lower supply terminal and asecond higher supply terminal; operating at least one low-voltage devicein a third voltage domain lower than the second voltage domain, whereinthe high-side region is isolated from the low-side region and thelow-voltage region; providing a first electrostatic protection to the atleast one high-side device based on a first electrostatic devicearranged in the first voltage domain and connected to the first pair ofsupply terminals and based on a second electrostatic device connected tothe first lower supply terminal of the first pair of supply terminalssuch that the third electrostatic device is coupled in series with thefirst electrostatic device; and providing a second electrostaticprotection to the at least one low-side device based on a thirdelectrostatic device arranged in the second voltage domain and connectedto the second pair of supply terminals.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments are described herein making reference to the appendeddrawings.

FIG. 1 is a schematic block diagram illustrating a control actuator 10of a power semiconductor device according to one or more embodiments;

FIG. 2 is a schematic block diagram of a first power module according toone or more embodiments;

FIG. 3A is a schematic block diagram of a second power module accordingto one or more embodiments; and

FIG. 3B is a schematic block diagram of a third power module accordingto one or more embodiments.

DETAILED DESCRIPTION

In the following, details are set forth to provide a more thoroughexplanation of the exemplary embodiments. However, it will be apparentto those skilled in the art that embodiments may be practiced withoutthese specific details. In other instances, well-known structures anddevices are shown in block diagram form or in a schematic view ratherthan in detail in order to avoid obscuring the embodiments. In addition,features of the different embodiments described hereinafter may becombined with each other, unless specifically noted otherwise.

Further, equivalent or like elements or elements with equivalent or likefunctionality are denoted in the following description with equivalentor like reference numerals. As the same or functionally equivalentelements are given the same reference numbers in the figures, a repeateddescription for elements provided with the same reference numbers may beomitted. Hence, descriptions provided for elements having the same orlike reference numbers are mutually exchangeable.

In this regard, directional terminology, such as “top”, “bottom”,“below”, “above”, “front”, “behind”, “back”, “leading”, “trailing”,etc., may be used with reference to the orientation of the figures beingdescribed. Because parts of embodiments can be positioned in a number ofdifferent orientations, the directional terminology is used for purposesof illustration. It is to be understood that other embodiments may beutilized and structural or logical changes may be made without departingfrom the scope defined by the claims. The following detaileddescription, therefore, is not to be taken in a limiting sense.Directional terminology used in the claims may aid in defining oneelement's spatial or positional relation to another element or feature,without being limited to a specific orientation.

It will be understood that when an element is referred to as being“connected” or “coupled” to another element, it can be directlyconnected or coupled to the other element or intervening elements may bepresent. In contrast, when an element is referred to as being “directlyconnected” or “directly coupled” to another element, there are nointervening elements present. Other words used to describe therelationship between elements should be interpreted in a like fashion(e.g., “between” versus “directly between,” “adjacent” versus “directlyadjacent,” etc.).

In embodiments described herein or shown in the drawings, any directelectrical connection or coupling, i.e., any connection or couplingwithout additional intervening elements, may also be implemented by anindirect connection or coupling, i.e., a connection or coupling with oneor more additional intervening elements, or vice versa, as long as thegeneral purpose of the connection or coupling, for example, to transmita certain kind of signal or to transmit a certain kind of information,is essentially maintained. Features from different embodiments may becombined to form further embodiments. For example, variations ormodifications described with respect to one of the embodiments may alsobe applicable to other embodiments unless noted to the contrary.

The terms “substantially” and “approximately” may be used herein toaccount for small manufacturing tolerances (e.g., within 5%) that aredeemed acceptable in the industry without departing from the aspects ofthe embodiments described herein. For example, a resistor with anapproximate resistance value may practically have a resistance within 5%of that approximate resistance value.

In the present disclosure, expressions including ordinal numbers, suchas “first”, “second”, and/or the like, may modify various elements.However, such elements are not limited by the above expressions. Forexample, the above expressions do not limit the sequence and/orimportance of the elements. The above expressions are used merely forthe purpose of distinguishing an element from the other elements. Forexample, a first box and a second box indicate different boxes, althoughboth are boxes. For further example, a first element could be termed asecond element, and similarly, a second element could also be termed afirst element without departing from the scope of the presentdisclosure.

One or more aspects of the present disclosure may be implemented as anon-transitory computer-readable recording medium having recordedthereon a program embodying methods/algorithms for instructing theprocessor to perform the methods/algorithms. Thus, a non-transitorycomputer-readable recording medium may have electronically readablecontrol signals stored thereon, which cooperate (or are capable ofcooperating) with a programmable computer system such that therespective methods/algorithms are performed. The non-transitorycomputer-readable recording medium can be, for example, a CD-ROM, DVD,Blu-ray disc, a RAM, a ROM, a PROM, an EPROM, an EEPROM, a FLASH memory,or an electronic memory device.

Each of the elements of the present disclosure may be configured byimplementing dedicated hardware or a software program on a memorycontrolling a processor to perform the functions of any of thecomponents or combinations thereof. Any of the components may beimplemented as a central processing unit (CPU) or other processorreading and executing a software program from a recording medium such asa hard disk or a semiconductor memory device. For example, instructionsmay be executed by one or more processors, such as one or more CPUs,digital signal processors (DSPs), general-purpose microprocessors,application-specific integrated circuits (ASICs), field programmablelogic arrays (FPGAs), programmable logic controller (PLC), or otherequivalent integrated or discrete logic circuitry.

Accordingly, the term “processor,” as used herein refers to any of theforegoing structures or any other structure suitable for implementationof the techniques described herein. A controller including hardware mayalso perform one or more of the techniques of this disclosure. Acontroller, including one or more processors, may use electrical signalsand digital algorithms to perform its receptive, analytic, and controlfunctions, which may further include corrective functions. Suchhardware, software, and firmware may be implemented within the samedevice or within separate devices to support the various techniquesdescribed in this disclosure.

Many functions of modern devices in automotive, consumer and industrialapplications, such as converting electrical energy and driving anelectric motor or an electric machine, rely on power semiconductordevices. For example, Insulated Gate Bipolar Transistors (IGBTs), MetalOxide Semiconductor Field Effect Transistors (MOSFETs) and diodes, toname a few, have been used for various applications including, but notlimited to switches in power supplies and power converters.

A power semiconductor device usually comprises a semiconductor structureconfigured to conduct a load current along a load current path betweentwo load terminal structures or load electrodes (e.g., thesource/emitter and the drain/collector) of the device. Further, the loadcurrent path may be controlled by means of a control electrode,sometimes referred to as gate electrode. For example, upon receiving acorresponding control signal from, e.g., a driver unit, the controlelectrode may set the power semiconductor device in one of a conductingstate or a blocking state. A control signal may by a voltage signal or acurrent signal having a controlled value.

A power transistor, also referred to as a power switch or a transistorswitch, is a power semiconductor device that may be used to drive a loadcurrent. For example, an IGBT is turned “ON” or “OFF” by activating anddeactivating its gate terminal. Applying a positive input voltage signalacross the gate and the emitter will keep the device in its “ON” state,while making the input gate signal zero or slightly negative will causeit to turn “OFF”. There is a turn-on process and a turn-off process forswitching the power transistor on and off.

During the turn-on process, a gate driver integrated circuit (IC) may beused to provide (source) a gate current (i.e., an ON current) to thegate of the power transistor in order to charge the gate to a sufficientvoltage to turn on the device. In particular, current Io+ is a gatedriver output current used to rise (i.e., charge) the gate of the powertransistor during a turn on transient. Thus, it is used to turn on thepower transistor.

In contrast, during the turn-off process, the gate driver IC is used todraw (sink) a gate current (i.e., an off current) from the gate of thepower transistor in order to discharge the gate sufficiently to turn offthe device. Current Io− is a gate driver output current used todischarge the gate of the power transistor during a turn off transient.Thus, it is used to turn off the power transistor.

A voltage pulse may be output from the gate driver IC as the controlsignal according to a pulse width modulation (PWM) scheme. Thus, thecontrol signal may be switched between an ON voltage level and an OFFvoltage level during a PWM cycle for controlling a power transistor.This in turn charges and discharges the gate voltage to turn on and offthe power transistor, respectively.

In particular, the gate of a power transistor is a capacitive load, andthe turn ON current (i.e., gate sourcing current) and the turn OFFcurrent (i.e., gate sinking current) are specified as the initialcurrent when a switching event is initiated. During a turn OFF event,after some small amount of time (small compared to the PWM period), thegate current decreases and reaches a zero value when the gate reaches,for example, 0V. During a turn ON event, after some small amount of time(small compared to the PWM period), the gate current decreases andreaches a zero value when the gate reaches, for example, 15V.

Transistors may include Insulated Gate Bipolar Transistors (IGBTs) andMetal Oxide Semiconductor Field Effect Transistors (MOSFETs) (e.g., SiMOSFETs or SiC MOSFETs). While IGBTs may be used as an example in theembodiments below, it will be appreciated that MOSFETs may besubstituted for the IGBTs and vice versa. In this context, whensubstituting a MOSFET for an IGBT, a MOSFET's drain may be substitutedfor an IGBT's collector, the MOSFET's source may be substituted for theIGBT's emitter, and the MOSFETs drain-source voltage VDS may besubstituted for the IGBT's collector-emitter voltage VCE in any one ofthe examples described herein. Thus, any IGBT module may be substitutedby a MOSFET module and vice versa.

Specific embodiments described herein pertain to, without being limitedthereto, a power semiconductor device that may be used within a powerconverter or a power supply. Thus, in an embodiment, the powersemiconductor device may be configured to carry a load current that isto be supplied to a load and/or, respectively, that is provided by apower source. For example, the semiconductor device may comprise one ormore power semiconductor cells, such as a monolithically integrateddiode cell, and/or a monolithically integrated transistor cell. Suchdiode cell and/or such transistor cells may be integrated in a powersemiconductor module.

Power semiconductor devices that include transistors which are suitablyconnected to form half-bridges are commonly used in the field of powerelectronics. For example, half-bridges may be used for driving electricmotors or switched mode power supplies.

For example, a multi-phase inverter is configured to provide multi-phasepower by supplying multiple phase loads (e.g., a three-phase motor). Forinstance, three-phase power involves three symmetrical sine waves thatare 120 electrical degrees out of phase with one another. In a symmetricthree-phase power supply system, three conductors each carry analternating current (AC) of the same frequency and voltage amplituderelative to a common reference but with a phase difference of one thirdthe period. Due to the phase difference, the voltage on any conductorreaches its peak at one third of a cycle after one of the otherconductors and one third of a cycle before the remaining conductor. Thisphase delay gives constant power transfer to a balanced linear load. Italso makes it possible to produce a rotating magnetic field in anelectric motor.

A three-phase inverter includes three inverter legs, one for each of thethree phases, and each inverter leg is connected to a direct current(DC) voltage source in parallel to each other. Each inverter legincludes a pair of power transistors, for example, arranged in ahalf-bridge configuration for converting DC to AC. In other words, eachinverter leg includes two complementary transistors (i.e., a high-sidetransistor and a low-side transistor) connected in series and whichswitch on and off complementary to the each other for driving a phaseload.

FIG. 1 is a schematic block diagram illustrating a control actuator 10of a power semiconductor device according to one or more embodiments. Inthis example, the control actuator 100 is a motor control actuator forcontrolling and driving a motor. However, it will be appreciated thatthe control actuator 100 may control and/or drive other types of loads.As such, FIG. 1 illustrates a non-limiting example of one use of thecontrol actuator with the motor being one possible type of load.

The control actuator 10 includes a power inverter 1 and an invertercontrol unit 2. The inverter control unit 2 behaves as a control unit(e.g., motor control unit) and thus may also be referred to as acontroller or a control IC (e.g., a motor controller or motor controlIC). The control unit may be a monolithic IC or may be split into amicrocontroller and a gate driver on two or more ICs.

In this example, the control actuator 10 is further coupled to athree-phase motor M, that includes three phases U, V, and W. The powerinverter 1 is a three-phase current generator configured to providethree-phase power by supplying three phase currents to drive the motorM. It will be further appreciated that the power inverter 1 and theinverter control unit 2 may be placed on a same circuit board, or onseparate circuit boards.

Deviations in both magnitude and phase may case a loss in power andtorque in the motor M. Therefore, the control actuator 10 may beconfigured to monitor and control the magnitude and phase of thecurrents supplied to the motor M in real-time to ensure the propercurrent balance is maintained based on a feedback control loop. Openloop motor control units also exist and may be implemented.

The power inverter 1 includes a switching array of six transistormodules 3 u+, 3 u−, 3 v+, 3 v−, 3 w+, and 3 w−(collectively referred toas transistor modules 3) arranged in complementary pairs. Eachcomplementary pair constitutes one inverter leg that supplies a phasecurrent to the three-phase motor M. Thus, each inverter leg includes anupper (high-side) transistor module 3 and a lower (low-side) transistormodule 3. Each transistor module may include one transistor, and mayalso include a diode (not shown). Thus, each inverter leg includes anupper transistor (i.e., a high-side switch) and a lower transistor(i.e., a low-side switch). Load current paths U, V, and W extend from anoutput of each inverter leg (i.e., the output of each half-bridge)located between complementary transistors and are configured to becoupled to a load, such as motor M. The power inverter 1 is coupled to aDC power supply 4 (e.g., a battery or a diode bridge rectifier) and tothe inverter control unit 2.

In this example, the inverter control unit 2 includes a motor controlcircuit and a gate driver circuit for controlling the switching array.In some examples, the inverter control unit 2 may be monolithic in whichthe motor control circuit and gate driver circuit are integrated onto asingle die. In other examples, the motor control circuit and gate drivercircuit may be partitioned as separate ICs. A monolithic gate driver isa gate driver on a single silicon chip and may be further made withspecific high voltage (HV) technology. Furthermore, the gate driver ICmay be integrated on the power inverter 1 to form a power module.

The controller IC performs the control function of the control actuator10 in real-time. When driving a motor, the control function is a motorcontrol function can include either controlling a permanent magnet motoror an induction motor and can be configured as a sensorless control notrequiring the rotor position sensing, as a sensor based control withHall sensors and/or an encoder device, or as a combination of bothsensor based control (e.g., used at lower rotor speeds) and sensorlesscontrol (e.g., used at higher rotor speeds).

For example, the inverter control unit 2 includes a controller anddriver unit 5 that includes a microcontroller unit (MCU) as thecontroller IC and a gate driver IC for generating driver signals forcontrolling the transistors of each transistor module 3. Thus, loadcurrent paths U, V, and W may be controlled by the controller and driverunit 5 by means of controlling the control electrodes (i.e., gateelectrodes) of the transistors 3. For example, upon receiving a controlsignal from the microcontroller, the gate driver IC may set acorresponding transistor in one of a conducting state (i.e., on-state)or a blocking state (i.e., off-state).

The gate driver IC may be configured to receive instructions, includingthe power transistor control signals, from the MCU, and turn on or turnoff respective transistors 3 in accordance with the receivedinstructions and control signals. For example, during the turn-onprocess of a respective transistor 3, the gate driver IC may be used toprovide (source) a gate current to the gate of the respective transistor3 in order to charge the gate. In contrast, during the turn-off process,the gate driver IC may be used to draw (sink) a gate current from thegate of the transistor 3 in order to discharge the gate.

The inverter control unit 2 or the controller and driver unit 5 itselfmay include a PWM controller, an ADC, a DSP, and/or a clock source(i.e., a timer or counter) used in implementing a PWM scheme forcontrolling the states of each transistor, and, ultimately, each phasecurrent provided on the respective load current paths U, V, and W.

In particular, the microcontroller of the controller and driver unit 5may use a motor control algorithm, such as a field-oriented control(FOC) algorithm, for providing current control in real-time for eachphase current output to a multi-phase load, such a multi-phase motor.For example, during FOC, a motor phase current should be measured suchthat an exact rotor position can be determined in real-time. Toimplement the determination of the motor phase current, the MCU 5 mayemploy an algorithm (e.g., space vector modulation (SVM), also referredas space vector pulse width modulation (SVPWM)) that uses single-shuntcurrent sensing.

Furthermore, the switches 3 (i.e., transistors) of the power inverter 1are controlled so that at no time are both switches in the same inverterleg turned on or else the DC supply would be shorted. This requirementmay be met by the complementary operation of the switches 3 within aninverter leg according to the motor control algorithm.

FIG. 2 is a schematic block diagram of a power module 200A according toone or more embodiments. The power module 200A includes a single-phasedrive stage 10 (i.e., an inverter leg) and a gate driver IC 20Aelectrically coupled to the single-phase drive stage 10. However, thesingle-phase drive stage may be expanded to a multiple-phase drive stateby adding additional inverter legs. Both the single-phase drive stage 10and the gate driver IC 20A are integrated into a single package (notillustrated). Thus, the power module 200A is packaged as a singledevice.

The single-phase drive stage 10 includes a low-side transistor 11 and ahigh-side transistor 12 that are controlled for supplying a load currentL_(OAD) to a one phase of a load (not illustrated). Freewheeling diodesD1 and D2 coupled to their respective power transistors 11 and 12 arealso shown.

The gate driver IC 20A is a monolithic high voltage (HV) gate driver,that includes a low-side (LS) gate driver 21 used to drive the low-sidetransistor switch 11 and a high-side (HS) gate driver 22 used to drivethe high-side transistor switch 12. As will be explained later, the LSgate drive 21 and the HS gate driver 22 are located in different voltagedomains of the gate driver IC 20A.

Both gate drivers 21 and 22 perform gate driving of their respectivepower transistor 11 and 12 based on digital PWM signals LIN and HINreceived from a microcontroller unit (MCU). The PWM signals are controlsignals received from the MCU at PWM logic 35 of the gate driver IC 20A.The PWM logic 35 receives the LIN and HIN signals from the MCU and deadtime logic 36 (e.g., a delay circuit) ensures there is a minimum deadtime implemented to prevent bridge shoot through. In someimplementations, the dead time logic 36 may be integrated in the PWMlogic 35. Eventually, the respective PWM control signals are passed onto the respective low-side and high-side gate driver 21 and 22, wherethe PWM signal HIN to the high-side gate driver 22 is passed through alow-voltage (LV) to high-voltage (HV) (LV/HV) level shifter 25. Afterthis point, the low-side and high-side gate driver 21 and 22 performgate driving.

LV/HV level shifter 25 is configured to convert a low-voltage signalinto its higher-voltage equivalent. For example, a logic low LV signalmay be converted into a logic low HV signal. Similarly, a logic high LVsignal may be converted into a logic high HV signal. This enablessignals to be transmitted across different voltage domains.

Both gate drivers 21 and 22 include separate pre-driver circuitry 26 and27 and buffers 33 and 34, respectively. The pre-driver circuitries 26and 27 are configured to receive the PWM signals and, based thereon,control the on/off state of a respective first current source, such as asource FET, used to generate current Io+. Additionally, the pre-drivercircuitries 26 and 27 are configured to receive the PWM signals and,based thereon, control the on/off state of a respective second currentsource, such as a sink FET, used to generate current Io−. The respectivecurrent sources are provided in buffers 33 and 34. Thus, the buffers 33and 34 may each include a pair of complementary FETs used to generateturn-on currents Io+ and turn-off currents Io− for their respectivepower transistor 11 and 12. Each of the pre-driver circuitries 26 and 27may further command a respective buffer 33 or 34 to use a certaincurrent capability.

The low-side gate driver 21 is arranged in a low-side region defined bya medium voltage domain, whereas the high-side gate driver is arrangedin high-side region defined by a high voltage domain. In practice, thegate driver IC 20A also includes a termination region that isolates thehigh voltage domain from the low voltage domain, and may be referred toas an isolation termination region. Thus, the termination regionprovides a voltage isolation barrier between the two voltage domains.

The gate driver IC 20A may be configured to receive PWM control signals,from an MCU, and turn on or turn off respective transistors 11 and 12 inaccordance with the received PWM control signals. For example, duringthe turn-on process of a respective transistor 11 or 12, the gate driverIC 20A may be used to provide (source) a gate current to the gate of therespective transistor 11/12 in order to charge the gate. In contrast,during the turn-off process, the gate driver IC 20A may be used to draw(sink) a gate current from the gate of the transistor 11/12 in order todischarge the gate.

Thus, the MCU is electrically coupled to the gate driver IC 20A for thetransmission of information signals and control signals HIN and LINtherebetween, and the gate driver IC 20A is electrically coupled to theinverter leg 10 for driving the power transistors thereof.

Specifically, the MCU is configured to generate PWM control signals LINand HIN for controlling the transistors 11 and 12, respectively, andtransmit the control signals to the gate driver IC 20A at the LV domain43. For example, the gate driver IC 20A is configured to receiveinstructions from the MCU to drive a load phase (i.e., an inverter leg)connected to voltage VS using the PWM control signals. These PWM controlsignals are received by the gate driver IC 20A at the LV domain (i.e.,at input pins HIN and LIN) and passed through to the correspondingpre-driver circuitry 26 and 27 via the appropriate logic (e.g., the PWMlogic 35 and, for the high-side, the level shifter 25). The buffers 33and 34 are configured to receive the PWM control signals and drive thecorresponding power transistor 11 and 12 via output terminals HO and LOof the gate driver IC 20A.

At least four regions, a HV domain 41, a medium-voltage domain (MV)domain 42 or mid-voltage domain, a LV domain 43, and a terminationregion 44 are monolithically built in a single integrated circuit. TheLV domain 43 is a region that includes low-voltage devices, the MVdomain 42 is a region that includes mid-voltage devices, and the HVdomain 41 is a region that includes high-voltage devices. For example,low-voltage devices may be supplied with 0-5V, mid-voltage devices maybe supplied with 0-30V, and high-voltage devices may be supplied withover 100 volts (e.g., 120V-160V). The voltage domains are not limited tothese voltage ranges, but are instead intended to provide an example ofone implementation. Nevertheless, general principle of different voltagedomain levels at different voltage hierarchies remains intact.

The termination region 44 is represented by the dotted line between thedifferent voltage domains. The termination region 44 isolates thedifferent voltage domains from each other, and may be referred to as anisolation termination region. Thus, the termination region 44 provides avoltage isolation barrier between the two voltage domains. Thetermination region 44 may be a unitary contiguous region or it maycomprise two or more regions that are used to separate the variousvoltage domains.

While FIG. 2 shows an example comprising three isolated voltage domains,some embodiments may have a configuration in which there is no isolationbetween the MV domain 42 and the LV domain 43. In other words, theportion of the termination region 44 between the MV domain 42 and the LVdomain 43 shown in FIG. 2 may not be present. In this case, thetermination region 44 remains between the HV domain 41 and the othervoltage domains 42 and 43 in order to isolate the HV domain 41therefrom.

In addition, some embodiments may have a configuration in which the LVdomain 43 is arranged entirely within the MV domain 42. In this case,the LV domain 43 may be a voltage island completely enclosed by atermination region 44 in order to isolate the LV domain 43 from the MVdomain 42. Additionally, a termination region 44 remains between the HVdomain 41 and the MV voltage domain 42 in order to isolate the HV domain41 from the MV domain 42. Accordingly, the LV domain 43 is isolated fromthe MV domain 42, and the HV domain 41 is isolated from the MV domain42. In naturally follows that the LV domain 43 and the HV domain 41 arealso isolated from each other by two separate termination regions 44.

Furthermore, while FIG. 2 shows an example comprising three voltagedomains, it will be appreciated that the number of voltage domains canbe reduced to two. In this case, respective components of the MV domain42 and the LV domain 43 may be combined into the same voltage domain(e.g., an LV domain or an MV domain) such that they are incorporatedinto a same voltage region. The remaining region may comprise the HVdomain 41 as shown in FIG. 2 that is isolated from the other voltagedomain.

All four regions 41-44 are built on a single silicon die to create asingle IC gate driver. The main purpose of the termination region 44,which may be arranged as discussed above, is to electrically isolate thedifferent voltage domains from each other. The termination region 44 mayinclude a large diode (not illustrated) usually used as bootstrap diodeto charge a bootstrap capacitor 24. The level shifter 25 is used toconvert (i.e., level shift) the voltage level of control signals, andthus transfer control information, from the low voltage/power domain tothe high voltage/power domain.

In addition, VB refers to the high-side floating supply voltage; VSrefers to the high-side floating ground voltage; VDD or VCC refers tothe low-side and logic fixed supply voltage; VSS or VEE refers to alow-side ground voltage; HO refers to the high-side floating outputvoltage; LO refers to the low-side output voltage; DC+ refers to DC-linkpositive; DC− refers to DC-link negative; and HIN and LIN refers to thelogic input voltages (i.e., control signals) received from the MCU.

In this and the following examples, VB operates at a maximum of 160V, VSoperates at a maximum of 130V, VCC operates at 30V, and VSS operates at0V. In particular, VS is equal to DC+ when transistor 12 is on (andtransistor 11 is off) and equal to DC− when transistor 11 is on (andtransistor 12 is off). In both cases, VB remains at substantially 30Vabove VS due to the bootstrap capacitor 24. Thus, the low-side(external) supply voltage that supplies VCC may be set to 30V and thehigh-side supply voltage VB may be operated at a maximum voltage of 160Vwhen DC+ is 130V. DC− is tied to ground/VSS but does not have to be.

It is also noted that the voltage difference between VB and VS issubstantially equal to the voltage difference between VCC and VSS. As aresult, LO is modulated between 0V and 30V and HO is modulated between130V and 160V. In some implantations VS may operate as high as 140V andVCC may operate as low as 20V. Other implementations may use othervoltage settings for each pad of the IC.

The aforementioned voltages are set such that the high-side voltagedomain operates in a higher voltage or power domain than that of thelow-side voltage domain. In addition, the medium-voltage or power domainis set at an intermediate level between the HV domain and the LV domain.

The HV domain 41 includes pre-driver circuitry 27, buffer 34, and a MVESD device 51 coupled to VS and VB.

The LV domain 43 includes PWM logic 35 and dead time logic 36. The levelshifter 25 spans across the termination region 44 between the HV domain41 and the LV domain 43.

The MV domain 42 includes pre-driver circuitry 26 and buffer 33. It alsoincludes a power management unit (PMU) 37 that is supplied by VSS andVCC. The PMU 37 includes circuitry that governs and regulates powerfunctions and converts the medium supply voltage (i.e., VCC) to a lowsupply voltage (e.g., 5V) that is supplied to the LV domain 43. Inparticular, PMU 37 supplies the low supply voltage to the PWM logic 35.The PWM logic 35 uses the low supply voltage to perform its functions.Secondly, the PMU 37 is configured to monitor for faults and turn offthe supply to the PWM logic 35 in the event an event occurs. By turningoff the supply to the PWM logic 35, the PWM logic 35 is disabled and thehigh-side transistor 12 is turned off.

The MV domain 42 further includes an MV ESD device 52 coupled to VSS andVCC and an HV ESD device 53 coupled to VSS and VS. As a result of the HVESD device 53 being connected to VS, the HV ESD device 53 and the MV ESDdevice 51 are coupled together in series to form a chain of ESC devices.

This configuration uses two ESD devices 51 and 53 in series such thatthe MV ESD device 51 shares HV ESD protection with the HV ESD device 53.The HV ESD device 53 protects a floating voltage domain tied to thehigh-side floating ground voltage VS and additionally assists the MV ESDdevice 51 to protect the HV domain 41. When used in this manner, the HVdomain 41 is protected by using two smaller ESD devices than would havebeen required if a single, dedicated ESD device was used to protect theHV domain 41. The silicon area of the two ESD devices 51 and 53 requiredon the chip is less than a total area that would have been required if asingle, dedicated ESD device was used to protect each voltage domainseparately. Thus, the configuration in the present example is able tosave some area because the HV ESD protection is being shared between twovoltage domains. Thus, both savings in area and cost can be realizedusing this configuration. Furthermore, the MV ESD device 52 is used toprotect the MV domain 42.

It is noted that the ESD devices 51, 52, and 53 are voltage leveltriggered devices, as opposed to being edge triggered devices. In otherwords, ESD protection is triggered by an ESD device when the voltageacross the ESD device reaches a threshold level (e.g., 30V or some otherdelta voltage). When the threshold voltage is reached, the clamp isactivated. This in contrast to edge triggered, which triggers an ESDprotection when a slope of a voltage increase across the device exceedsa slope threshold (e.g., 30V/us). Fast movements in voltage changes aretypical in gate driver applications. Thus, edge triggered devices mayresult in frequent and unwanted clamping caused by these fast voltagemovements. Using voltage level triggered devices prevents unwantedclamping by setting a threshold voltage level that must be reachedbefore clamping is activated.

The ESD devices 51, 52, and 53 may be silicon controlled rectifier(SCR)-based devices. Thus, the ESD devices 51, 52, and 53 includecircuitry configured for voltage level triggered ESD protection. Forexample, when there is a certain voltage across the protection devicethere is a snapback effect that causes a voltage clamping. As a result,the circuitry connected in parallel to the corresponding ESD deviceproviding the ESD protection is saved.

FIG. 3A is a schematic block diagram of a power module 300A according toone or more embodiments. The power module 300A is similar to powermodule 200A, with the exception that the gate driver IC 30A has its HVESD device 53 connected to VCC instead of to VSS. As a result of the HVESD device 53 being connected to VS and to VCC, the HV ESD device 53,the MV ESD device 51, and the MV device 52 are coupled together inseries to form a chain of ESC devices.

This configuration uses three ESD devices 51, 52, and 53 in series suchthat the MV ESD device 51 shares HV ESD protection with a second ESDdevice 53 and a third ESD device 52. The HV ESD device 53 protects thefloating voltage domain tied to the high-side floating ground voltage VSand additionally assists the MV ESD device 51 to protect the HV domain41. Additionally, the MV ESD device 52 protects the MV domain 42 as wellas assists in protecting the HV domain 41.

When used in this manner, the HV domain 41 is protected by using threesmaller ESD devices than would have been required if a single ESD devicewas used to protect the HV domain 41. The silicon area of the three ESDdevices 51, 52, and 53 required on the chip is less than a total areathat would have been required if a single, dedicated ESD device was usedto protect each voltage domain separately. In contrast, theconfiguration in the present example is able to save some area becausethe HV ESD protection is being shared between two voltage domains. Thus,both savings in area and cost can be realized using this configuration.

Aside from this difference, the configuration of the gate driver IC 30Ais the same as the configuration of the gate driver IC 20A.

FIG. 3B is a schematic block diagram of a power module 300B according toone or more embodiments. The power module 300B is similar to powermodule 300A, with the exception that the gate driver IC 30B includes anadditional voltage domain, floating voltage (FV) domain 45. The FVdomain 45 includes the HV ESD device 53 and is isolated from the othervoltage domains 41, 42, and 43 by the termination region 44. The FVdomain 45 includes voltage levels that float between the MV domain 42and the HV domain 41. Aside from these differences, the configuration ofthe gate driver IC 30B is the same as the configuration of the gatedriver IC 30A.

Embodiments further include a method of operating a gate driverintegrated circuit, including operating at least one high-side device ina first voltage domain according to a first pair of supply terminalsthat include a first lower supply terminal and a first higher supplyterminal; operating at least one low-side device in a second voltagedomain lower than the first voltage domain according to a second pair ofsupply terminals that include a second lower supply terminal and asecond higher supply terminal; operating at least one low-voltage devicein a third voltage domain lower than the second voltage domain, whereinthe high-side region is isolated from the low-side region and thelow-voltage region; providing a first electrostatic protection to the atleast one high-side device based on a first electrostatic devicearranged in the first voltage domain and connected to the first pair ofsupply terminals and based on a second electrostatic device connected tothe first lower supply terminal of the first pair of supply terminalssuch that the third electrostatic device is coupled in series with thefirst electrostatic device; and providing a second electrostaticprotection to the at least one low-side device based on a thirdelectrostatic device arranged in the second voltage domain and connectedto the second pair of supply terminals.

Embodiments further include methods of manufacturing any of thedescribed embodiments. The methods of manufacturing include forming thedifferent regions according to their voltage domains, forming one ormore termination regions where at least the high-side region is isolatedfrom the low-side region and the low-voltage region, and providing thecorresponding circuitry in each region/voltage domain. The circuitryincludes the ESD devices 51, 52, and 53 electrically connected in themanner described above in conjunction with FIGS. 2, 3A, and 3B.

For example, a method of manufacturing a gate driver integrated circuitmay include forming a high-side region that operates in a first voltagedomain according to a first pair of supply terminals that include afirst lower supply terminal and a first higher supply terminal; forminga low-side region that operates in a second voltage domain lower thanthe first voltage domain according to a second pair of supply terminalsthat include a second lower supply terminal and a second higher supplyterminal; forming a low-voltage region the operates in a third voltagedomain lower than the second voltage domain; forming at least onetermination region that electrically isolates the high-side region fromthe low-side region and the low-voltage region; providing a firstelectrostatic device arranged in the high-side region and connected tothe first pair of supply terminals; providing a second electrostaticdevice arranged in the low-side region and connected to the second pairof supply terminals; and providing a third electrostatic deviceconnected to the first lower supply terminal of the first pair of supplyterminals such that the third electrostatic device is coupled in serieswith the first electrostatic device.

While various embodiments have been disclosed, it will be apparent tothose skilled in the art that various changes and modifications can bemade which will achieve some of the advantages of the concepts disclosedherein without departing from the spirit and scope of the invention. Itwill be obvious to those reasonably skilled in the art that othercomponents performing the same functions may be suitably substituted. Itis to be understood that other embodiments may be utilized andstructural or logical changes may be made without departing from thescope of the present invention. It should be mentioned that featuresexplained with reference to a specific figure may be combined withfeatures of other figures, even in those not explicitly mentioned. Suchmodifications to the general inventive concept are intended to becovered by the appended claims and their legal equivalents.

Furthermore, the following claims are hereby incorporated into thedetailed description, where each claim may stand on its own as aseparate example embodiment. While each claim may stand on its own as aseparate example embodiment, it is to be noted that—although a dependentclaim may refer in the claims to a specific combination with one or moreother claims—other example embodiments may also include a combination ofthe dependent claim with the subject matter of each other dependent orindependent claim. Such combinations are proposed herein unless it isstated that a specific combination is not intended. Furthermore, it isintended to include also features of a claim to any other independentclaim even if this claim is not directly made dependent on theindependent claim.

It is further to be noted that methods disclosed in the specification orin the claims may be implemented by a device having means for performingeach of the respective acts of these methods. For example, thetechniques described in this disclosure may be implemented, at least inpart, in hardware, software, firmware, or any combination thereof,including any combination of a computing system, an integrated circuit,and a computer program on a non-transitory computer-readable recordingmedium. For example, various aspects of the described techniques may beimplemented within one or more processors, including one or moremicroprocessors, DSPs, ASICs, or any other equivalent integrated ordiscrete logic circuitry, as well as any combinations of suchcomponents.

Further, it is to be understood that the disclosure of multiple acts orfunctions disclosed in the specification or in the claims may not beconstrued as to be within the specific order. Therefore, the disclosureof multiple acts or functions will not limit these to a particular orderunless such acts or functions are not interchangeable for technicalreasons. Furthermore, in some embodiments, a single act may include ormay be broken into multiple sub acts. Such sub acts may be included andpart of the disclosure of this single act unless explicitly excluded.

* * *

What is claimed is:
 1. A gate driver integrated circuit, comprising: ahigh-side region that operates in a first voltage domain according to afirst pair of supply terminals that include a first lower supplyterminal and a first higher supply terminal; a low-side region thatoperates in a second voltage domain lower than the first voltage domainaccording to a second pair of supply terminals that include a secondlower supply terminal and a second higher supply terminal; a low-voltageregion the operates in a third voltage domain lower than the secondvoltage domain; at least one termination region that electricallyisolates the high-side region from the low-side region and thelow-voltage region; a first electrostatic device arranged in thehigh-side region and connected to the first pair of supply terminals; asecond electrostatic device arranged in the low-side region andconnected to the second pair of supply terminals; and a thirdelectrostatic device connected to the first lower supply terminal of thefirst pair of supply terminals such that the third electrostatic deviceis coupled in series with the first electrostatic device.
 2. The gatedriver integrated circuit of claim 1, wherein the first electrostaticdevice has a first voltage rating, the second electrostatic device hasthe first voltage rating, and the third electrostatic device has asecond voltage rating greater than the first voltage rating.
 3. The gatedriver integrated circuit of claim 2, wherein the first voltage ratingis less than 100V and the second voltage rating is at least 100V.
 4. Thegate driver integrated circuit of claim 3, wherein the first voltagerating is 30V or less.
 5. The gate driver integrated circuit of claim 1,wherein the third electrostatic device is connected to the second lowersupply terminal of the second pair of supply terminals.
 6. The gatedriver integrated circuit of claim 1, wherein the third electrostaticdevice is connected to the second higher supply terminal of the secondpair of supply terminals such that the third electrostatic device iscoupled in series with both the first electrostatic device and thesecond electrostatic device.
 7. The gate driver integrated circuit ofclaim 6, wherein the third electrostatic device is coupled between thefirst electrostatic device and the second electrostatic device.
 8. Thegate driver integrated circuit of claim 6, wherein the firstelectrostatic device has a first voltage rating, the secondelectrostatic device has the first voltage rating, and the thirdelectrostatic device has a second voltage rating greater than the firstvoltage rating.
 9. The gate driver integrated circuit of claim 1,further comprising: a high-side gate driver disposed in the high-sideregion and connected to the first pair of supply terminals, wherein thehigh-side gate driver is configured to generate an on-current during aplurality of turn-on switching events to drive a high-side transistor; alow-side gate driver disposed in the low-side region and connected tothe second pair of supply terminals, wherein the low-side gate driver isconfigured to drive a low-side power transistor complementary to thehigh-side power transistor; and a pulse width modulator (PWM) logiccircuit disposed in the low-voltage region, wherein the PWM logiccircuit is configured to receive high-side PWM control signals andlow-side PWM control signals, transmit the high-side PWM control signalsto the high-side gate driver, and transmit the low-side PWM controlsignals to the low-side gate driver.
 10. The gate driver integratedcircuit of claim 9, further comprising: a power management unit disposedin the low-side region and connected to the second pair of supplyterminals, wherein the power management unit is configured to convert avoltage received from the second higher supply terminal into a lowervoltage and supply the lower voltage to the PWM logic circuit.
 11. Thegate driver integrated circuit of claim 10, wherein the power managementunit is configured to monitor for a fault and, on a condition the faultis detected, disable supplying the lower voltage to the PWM logiccircuit.
 12. The gate driver integrated circuit of claim 1, furthercomprising: a floating voltage region that operates in a floatingvoltage domain between the first voltage domain and the second voltagedomain, wherein the at least one termination region electricallyisolates at least the high-side region, the low-side region, and thefloating voltage region from each other, and wherein the thirdelectrostatic device is disposed in the floating voltage region.
 13. Thegate driver integrated circuit of claim 12, wherein the at least onetermination region electrically isolates the high-side region, thelow-side region, the low-voltage region, and the floating voltage regionfrom each other.
 14. The gate driver integrated circuit of claim 12,wherein the third electrostatic device is connected to the second lowersupply terminal of the second pair of supply terminals.
 15. The gatedriver integrated circuit of claim 12, wherein the third electrostaticdevice is connected to the second higher supply terminal of the secondpair of supply terminals such that the third electrostatic device iscoupled in series with both the first electrostatic device and thesecond electrostatic device.
 16. The gate driver integrated circuit ofclaim 15, wherein the third electrostatic device is coupled between thefirst electrostatic device and the second electrostatic device.
 17. Thegate driver integrated circuit of claim 15, wherein the firstelectrostatic device has a first voltage rating, the secondelectrostatic device has the first voltage rating, and the thirdelectrostatic device has a second voltage rating greater than the firstvoltage rating.
 18. The gate driver integrated circuit of claim 1,wherein the gate driver integrated circuit is a monolithic gate driverintegrated circuit.
 19. The gate driver integrated circuit of claim 1,wherein the first electrostatic device, the first electrostatic device,and the first electrostatic device are silicon controlled rectifiers.20. The gate driver integrated circuit of claim 1, wherein the firstelectrostatic device, the first electrostatic device, and the firstelectrostatic device include at least one Zener diode.
 21. The gatedriver integrated circuit of claim 1, wherein: the first lower supplyterminal is configured to receive a high-side floating ground voltage,the first higher supply terminal is configured to receive a high-sidefloating supply voltage, the second lower supply terminal is configuredto receive a low-side ground voltage, and second higher supply terminalis configured to receive a low-side fixed supply voltage.
 22. The gatedriver integrated circuit of claim 1, wherein the at least onetermination region electrically isolates the high-side region, thelow-side region, and the low-voltage region from each other.
 23. Thegate driver integrated circuit of claim 1, wherein the thirdelectrostatic device is arranged in the low-side region.
 24. A method ofoperating a gate driver integrated circuit, the method comprising:operating at least one high-side device in a first voltage domainaccording to a first pair of supply terminals that include a first lowersupply terminal and a first higher supply terminal; operating at leastone low-side device in a second voltage domain lower than the firstvoltage domain according to a second pair of supply terminals thatinclude a second lower supply terminal and a second higher supplyterminal; operating at least one low-voltage device in a third voltagedomain lower than the second voltage domain, wherein the high-sideregion is isolated from the low-side region and the low-voltage region;providing a first electrostatic protection to the at least one high-sidedevice based on a first electrostatic device arranged in the firstvoltage domain and connected to the first pair of supply terminals andbased on a second electrostatic device connected to the first lowersupply terminal of the first pair of supply terminals such that thethird electrostatic device is coupled in series with the firstelectrostatic device; and providing a second electrostatic protection tothe at least one low-side device based on a third electrostatic devicearranged in the second voltage domain and connected to the second pairof supply terminals.
 25. The method of claim 24, wherein the high-sideregion, the low-side region, and the low-voltage region are electricallyisolated from each other.